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Journal Articles

Feasibility study of the one-dimensional radiation distribution sensing method using an optical fiber sensor based on wavelength spectrum unfolding

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Yamazaki, Atsushi*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo

Journal of Nuclear Engineering and Radiation Science, 7(4), p.042002_1 - 042002_7, 2021/10

For the application in the measurement of the high dose rate hot spots inside the Fukushima Daiichi Nuclear Power Station (FDNPS) buildings, we propose a novel one-dimensional radiation distribution sensing method using an optical fiber sensor based on wavelength spectrum unfolding. The proposed method estimates the incident position of radiation to the fiber by the unfolding of the wavelength spectrum output from the fiber edge using the fact that the attenuation length of light along the fiber depends on the wavelength. Because this method measures the integrated light intensity, this method can avoid the problem of counting loss and signal pile-up, which occurs in the radiation detector with pulse counting mode under high dose rate field. Through basic experiments using the ultraviolet light source and $$^{90}$$Sr/$$^{90}$$Y radioactive point source, basic properties of source position detection were confirmed.

Journal Articles

Evaluation of a one-dimensional position-sensitive quartz optical fiber sensor based on the time-of-flight method for high radiation dose rate applications

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*

Nuclear Instruments and Methods in Physics Research A, 996, p.165151_1 - 165151_8, 2021/04

 Times Cited Count:0 Percentile:0.03(Instruments & Instrumentation)

For the measurement of radiation distribution inside the Fukushima Daiichi Nuclear Power Station (FDNPS) buildings, the evaluation of a small-diameter quartz optical fiber as a one-dimensional position-sensitive sensor was conducted. The sensor determines the incident position of radiation into the fiber using the time-of-flight information of emitted Cerenkov photons in the optical fiber. Compared with the conventional sensor using the plastic scintillating fiber, the quartz optical fiber has much higher position resolution, which may be the result of the improvement of timing characteristics caused by the prompt emission mechanism of the Cerenkov radiation. Additionally, the response of position-sensitive quartz optical fiber sensor under high radiation field was evaluated, and good count rate linearity was confirmed using the 10 m long quartz optical fiber with a diameter of 0.4 mm up to the dose rate at least 20 mSv/h, and the radiation tolerance property up to the accumulated dose of 1 kGy was evaluated.

Journal Articles

Development of one-dimensional optical fiber type radiation distribution sensing method based on wavelength spectrum unfolding

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Yamazaki, Atsushi*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo

Proceedings of International Youth Nuclear Congress 2020 (IYNC 2020) (Internet), 4 Pages, 2020/05

Journal Articles

Pulsed neutron imaging based crystallographic structure study of a Japanese sword made by Sukemasa in the Muromachi period

Oikawa, Kenichi; Kiyanagi, Yoshiaki*; Sato, Hirotaka*; Omae, Kazuma*; Pham, A.*; Watanabe, Kenichi*; Matsumoto, Yoshihiro*; Shinohara, Takenao; Kai, Tetsuya; Harjo, S.; et al.

Materials Research Proceedings, Vol.15, p.207 - 213, 2020/02

Journal Articles

Photodisintegration cross section measurements on $$^{186}$$W, $$^{187}$$Re and $$^{188}$$Os; Implications for the Re-Os cosmochronology

Shizuma, Toshiyuki; Utsunomiya, Hiroaki*; Mohr, P.*; Hayakawa, Takehito; Goko, Shinji*; Makinaga, Ayano*; Akimune, Hidetoshi*; Yamagata, Tamio*; Ota, Masahisa*; Ogaki, Hideaki*; et al.

Physical Review C, 72(2), p.025808_1 - 025808_9, 2005/08

 Times Cited Count:38 Percentile:88.71(Physics, Nuclear)

Cross sections of the $$^{186}$$W, $$^{187}$$Re, $$^{188}$$Os($$gamma,n$$) reactions were measured using quasi-monochromatic photon beams from laser Compton scattering (LCS) with average energies from 7.3 to 10.9 MeV. The results are compared with the predictions of Hauser-Feshbach statistical calculations using four different sets of input parameters. In addition, the inverse neutron capture cross sections were evaluated by constraining the model parameters, especially the $$E1$$ strength function, on the basis of the experimental data. The present experiment helps to further constrain the correction factor $$F_{sigma}$$ for the neutron capture on the 9.75 keV state in $$^{187}$$Os. Implications of $$F_{sigma}$$ to the Re-Os cosmochronology are discussed with a focus on the uncertainty in the estimate of the age of the Galaxy.

Journal Articles

Construction of 144, 565 keV and 5.0 MeV monoenergetic neutron calibration fields at JAERI

Tanimura, Yoshihiko; Yoshizawa, Michio; Saegusa, Jun; Fujii, Katsutoshi; Shimizu, Shigeru; Yoshida, Makoto; Shibata, Yasunari*; Uritani, Akira*; Kudo, Katsuhisa*

Radiation Protection Dosimetry, 110(1-4), p.85 - 89, 2004/09

 Times Cited Count:19 Percentile:77.18(Environmental Sciences)

Mono-energetic neutron calibration fields have been developed at the Facility of Radiation Standards (FRS) of JAERI using 4MV Van-de-Graaff (Pelletron) accelerator. The fields of 144 keV, 565 keV and 5.0 MeV neutrons were constructed with estimating neutron energy spectra and establishing the traceability of reference neutron fluence.

JAEA Reports

Basic study on ultra high sensitive neutron dosimetry technique based on resonant laser ablation, JAERI's nuclear research promotion program, H12-035 (Contract Research)

Iguchi, Tetsuo*; Watanabe, Kenichi*; Kawarabayashi, Jun*; Uritani, Akira*; Enokida, Yoichi*; Watanabe, Kazuo

JAERI-Tech 2004-010, 62 Pages, 2004/03

JAERI-Tech-2004-010.pdf:2.6MB

no abstracts in English

JAEA Reports

Feasibility Study on the High Reliable Radiation Detection System using Normal Optical Fiber

Tsujimura, Norio; Yoshida, T.; Kawarabayashi, Jun*; Mizuno, Ryoji*; Naka, Ryotaro*; Uritani, Akira*; Watanabe, Kenichi*

JNC TY8400 2003-010, 46 Pages, 2003/03

JNC-TY8400-2003-010.pdf:1.36MB

The authors developed a radiation distribution monitor using a normal optical fiber. This monitor has long operation length (10m - 100m) and can obtain continuous radiation distribution.

Journal Articles

Radioactivity measurements of $$^{192}$$Ir wire sources with a microcalorimeter

Genka, Tsuguo; ; Takeuchi, Norio; Uritani, Akira*; Mori, Chizuo*

Nuclear Instruments and Methods in Physics Research A, 339, p.398 - 401, 1994/00

 Times Cited Count:6 Percentile:58.06(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Direct measurement of gaseous activities by diffusion-in long proportional counter method

Yoshida, Makoto; *; Y.Wu*; *; Uritani, Akira*; Mori, Chizuo*

Nuclear Instruments and Methods in Physics Research A, 330, p.158 - 164, 1993/00

 Times Cited Count:9 Percentile:67.89(Instruments & Instrumentation)

no abstracts in English

Oral presentation

Crystallographic characterization on different types of structure (Tsukurikomi) of Japanese swords using pulsed neutron imaging and diffraction methods

Oikawa, Kenichi; Kiyanagi, Yoshiaki*; Shinohara, Takenao; Kai, Tetsuya; Watanabe, Kenichi*; Uritani, Akira*; Hori, Genki*; Hirata, Yuho*

no journal, , 

Oral presentation

Characterization of TOF scintillation fiber radiation sensor for high dose rate measurement

Terasaka, Yuta; Sato, Yuki; Watanabe, Kenichi*; Uritani, Akira*; Torii, Tatsuo

no journal, , 

no abstracts in English

Oral presentation

Basic study of one-dimensional optical fiber based radiation distribution sensing by wavelength spectroscopy

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Hanai, Tetsuya*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo

no journal, , 

For the reduction of the external dose of workers in the process of Fukushima Daiichi Nuclear Power Station (1F) decommissioning and to propose an effective decontamination plan, it is necessary to grasp the distribution of locally existing hotspots. A one-dimensional radiation distribution measurement system applying time-of-flight method to scintillating optical fiber has been widely applied after the 1F accident, but in a high dose rate environment such as 1F reactor building, a pile-up of signal and chance-coincidence effect of a sensor is a problem. Therefore, as an integral-type measurement method that can avoid problems such as pile-up, we propose a reverse-estimation method which measures the wavelength spectrum at the fiber edge and estimates the incident position of radiation to the fiber using the fact that the attenuation length of light depends on the wavelength.

Oral presentation

Japanese-sword crystallographic study based on pulsed neutron imaging at J-PARC

Oikawa, Kenichi; Kiyanagi, Yoshiaki*; Sato, Hirotaka*; Pham, A.*; Watanabe, Kenichi*; Matsumoto, Yoshihiro*; Shinohara, Takenao; Kai, Tetsuya; Harjo, S.; Onuma, Masato*; et al.

no journal, , 

Oral presentation

Development of optical fiber based novel wavelength-resolved type radiation distribution sensing method

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Yamazaki, Atsushi*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo

no journal, , 

We are developing a one-dimensional radiation distribution sensing method using optical fiber to measure the distribution of hot spots in the Fukushima Daiichi Nuclear Power Station (1F) buildings. As a new radiation distribution sensing technique applicable to high dose rate environments, a wavelength-resolved analysis method was developed. This method measures the emission wavelength spectrum derived from the interaction between the optical fiber and radiation on one side of the fiber and estimates the radiation incident position to the fiber reversely using the fact that the attenuation length of light along the fiber depends on the wavelength. In the presentation, we report the results of the principle verification of this method.

Oral presentation

One-dimensional radiation distribution sensing method based on wavelength spectrum unfolding of optical fiber

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo

no journal, , 

no abstracts in English

Oral presentation

Development of radiation distribution sensing method using one-dimensional optical fiber for Fukushima Daiichi NPS decommissioning

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo

no journal, , 

Oral presentation

Oral presentation

Development of radiation distribution sensing method based on wavelength spectrum unfolding using optical fiber sensor

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*

no journal, , 

no abstracts in English

Oral presentation

Development and verification of radiation distribution sensing method based on wavelength spectrum unfolding

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*

no journal, , 

no abstracts in English

22 (Records 1-20 displayed on this page)